metamorphic
Quartzite
Metamorphic Quartzite (SiO2)
Hardness of 7 on the Mohs scale, color ranges from white and gray to pink, red, or purple due to iron oxides, vitriform to greasy luster, massive to granular crystal structure, lacks prominent cleavage, specific gravity is approximately 2.65.
Identified More metamorphic →
Explore Quartzite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 7 on the Mohs scale, color ranges from white and gray to pink, red, or purple due to iron oxides, vitriform to greasy luster, massive to granular crystal structure, lacks prominent cleavage, specific gravity is approximately 2.65.
Formation & geological history
Formed from quartz-rich sandstone or chert under high temperature and pressure conditions associated with regional metamorphism, typically occurring during mountain-building events over millions of years.
Uses & applications
Used in construction, railroad ballast, crushed stone for road aggregates, decorative landscaping, and occasionally for specialty countertops and tiles.
Geological facts
Quartzite is extremely durable and resistant to chemical weathering, which is why ridges formed of quartzite often persist as prominent mountain crests. The famous peaks of the Appalachian Mountains and parts of the Swiss Alps contain significant quartzite layers.
Field identification & locations
Can be identified in the field by its sugary texture, conchoidal fracture that cuts through quartz grains rather than around them (unlike sandstone), and its inability to be scratched by a steel knife.
More like this
